Thursday, November 1, 2012

Russia's Answer to Their Own Acqua Alta

In the wake of Hurricane Sandy - we are seeing startling photos and video.  The east coast of the United States has been ravaged, many in the US and Caribbean have lost homes, property, and in too many cases, their lives. 
My most sincere prayers are with all of the folks in the areas that have been affected. Everyone concerned is giving some serious thought now to the effects of wind, loss of power, and of course high water.
They do this dance with the devil at least a few times a year in different parts of the southern and eastern US. 
Sometimes it's a near miss, other times tragedy strikes. 
Sandy is now one for the record books, as she is the first hurricane to hit New Jersey since Grover Cleveland was in office.
A quick look at a satellite image of the storm made it clear that this would be a storm that people would remember.

Meanwhile, our friends in Venice are quietly enduring an unwelcome guest of their own - one they play host to regularly this time of year. 

Nereo Zane tells me that they've got rain and strong winds.
As I write this René Seindal of Venice Kayak just posted on Facebook that the "high water" sirens are sounding again.
Another one of my friends in Venice recently posted a public praise on Facebook for the person who invented rubber boots.
And while it's not nearly as perilous as a hurricane,
the infamous "Acqua Alta" is back, doing damage of its own as it makes regular stops in La Serenissima.

Acqua Alta (which means "high water"), fills Piazza San Marco.
photo by Sean Antonioli

I'm not an expert on this high water phenomenon, and if you want to learn more about it there are plenty of resources online, but in a nutshell Acqua Alta is brought on when high tide is enhanced by northerly winds blowing up the Adriatic Sea
(Venice is at the end of the Adriatic - essentially a "wind alley").
I'm told that runoff from rain comes down the various tributaries that deposit into the lagoon, contributing to the overabundance of water around, and eventually in the city.
This trifecta of meteorological conditions is a regular reality in Venezia.
City workers set up a network of raised planks for people to walk around the city on.
some businesses loan out rubber boots to their patrons,
many locals break out their own "high water footwear" as well.

Raised walking planks and "high water footwear".
photo by Sean Antonioli

Meanwhile, municipal leaders have been speculating, talking, and arguing for a long time about a mechanical system to literally "stem the tide" and try to control Acqua Alta.  A plan was hatched and construction began in 2003 on a series of mechanical devices known as "MOSE" - named after Moses (you know, the whole "parting of the waters" thing, not riding down the river in a basket), a fitting name.
MOSE is a bold endeavor, one which I hope will be effective upon completion.  The last I heard, the project was to be completed in 2012, but I've learned to be a skeptic with government project schedules 
(in any country).

Whatever the case, I am looking forward to seeing MOSE in action at some point, and I hope its designers enjoy a great success of their creation. 
I wish we could come up with something to stop the hurricanes in this part of the world.

The MOSE system is a unique one, as unique as the city it is meant to protect - up at the end of a sea where wind can sometimes push a rising tide higher, but this isn't the only place where such a thing happens.

St. Petersburg, Russia has a long history of being flooded as well.  The city is located at the end of the Gulf of Finland (which extends east off of the Baltic Sea) with the Neva River coming in from the east.  When winds, tides, and rains have conspired, St. Petersburg has experienced over three hundred floods since her founding in 1703.
In 1955 they decided to do something about it.  A lot of planning and designing was involved, and the project was quite large.  Construction began in 1979.  Things were moving along at an even pace until the fall of the Soviet Union; work resumed in 2005 and was completed in 2011.

I was in St. Petersburg earlier this year.  My family and I went ashore for two days during a tour of the Baltic states.  A little while after our cruise ship left the dock in St. Petersburg, I stepped out onto the balcony as we passed by some amazing old islands that reminded me quite a lot of some places I'd seen in the Venetian lagoon.

Eventually the breakwater came into view and as we approached the opening between rock walls in the sea, I noticed a curious looking piece of aparatus.
What I saw was the very large and impressive set of mobile caissons that make up the "S-1 gate" of what is known as the St. Petersburg Flood Prevention Facility Complex - a series of man made elements which include breakwaters, dams, caissons, and a roadway which crosses the whole system and becomes a tunnel at one point.  In the middle of the whole thing is historic Kotlin Island. 

The St. Petersburg Flood Prevention Facility Complex is also referred to as the "St. Petersburg Dam". 

Getting construction back on track was important, and getting the system completed and operational in a timely manner was a priority to all, but Russian President Vladimir Putin decided that things needed to happen more quickly. 
My friend Maria Sigaeva was born and raised in St. Petersburg, she now works as a tour guide there.  Maria told me:

It is said that it was Putin (who is a native of the city) who hastened the fulfillment of the plan, and in 2011 there was an underground tunnel opened, which is now part of the Highway that connects two parts of our city (the North and the South). They used to be separated by the Gulf of Finland - and it took a long way to get from one part to another. Now it's only 30 minutes. So locals are very happy about it.

Putin is said to have moved the date of completion up by two years.
This may have brought stress on those involved in the project, but he knew that every year it took to close those gates...was another year that could see flooding.

I asked Maria if the system works and if there has been any sea surge.

Yes, the dam really saved the city two times by now - for example last December it was very warm and rainy and extra water came from the Baltic sea - that was the first time the dam was used. Later meteorologists said that if not for the dam the water in the city would go up to 1.5 meters.

Maria recalls a time before the caissons could be used:
And actually I clearly remember that several years ago some streets on one of the islands of the city were closed because they were flooded! Now it doesn't happen anymore.

So "what's a caisson?", you might ask.
We hear the word from time to time, seemingly with different meanings.
The word is french for "box", and has been used to describe many things. architectural features are sometimes described as caissons, but a lot of Americans recognize the word from the official song of the U.S. Army, which mentions how "those caissons go rolling along".  In the military application, a caisson is a rolling cart, which carries ammunition and artillery - this type of caisson probably started out as a rolling box - hence the name.

The caissons at the S-1 gate are yet another type of structure - in this case they are sealed underwater structures...and mighty big ones.

Each caisson is a "curved wall" with arms that allow it to swing out, think of it as a partial section of a giant wheel.  When the two pieces swing out from either side of the opening, they create an effective tide deterring mechanism.

The whole aparatus looks big from the water, but it's even larger than you might think, because the curved wall sits in a curved depression that's fifteen meters deep.

The curved wall, mostly concealed in its deep well-like depression.

Each caisson swings out, pivoting on a huge joint seen here:
I did some research hoping to find the "world's largest ball joint",
because I've never seen one so big.  It's just a guess, but I'll bet the two that swing out the caissons at the S-1 gate rank pretty high on the list.

A good overhead diagram of the design can be seen on this page.

The construction of these giant "moving gates" was supervised by a Russian company known as "Рубин" (in English it's "Rubin").
Their English-version website has a nice short page about the caissons, with a good overhead view of the closed gates.  In the Russian language, the "C" makes an "S" sound - probably why the Rubin site refers to this passageway as the "C-1".
Here's the link: "Floating Gate for Navigation Pass".

UK based Halcrow was another company involved with the project. 
Here's a link to one of their pages that gives a more detailed view into things.  Be sure to catch the video, which was produced before the project was completed, but is quite educational.
Here's the page:
"St Petersburg Flood Protection Barrier"

and the video in another link:
"St Petersburg Flood Barrier video"

One of the more unusual aspects of this temporary damming system,
is how it is deployed.
Each caisson is pushed into place using what some have called
a "Monster Train" - strong enough to move a lot of weight. 
To guarantee traction, these train engines roll on tracks that have teeth which interlock with their geared wheels.

Some good views of the "Monster Train" and other parts of the project can be seen on this page.  The photos were taken in 2010, before construction was complete.

There are some great shots of the caissons in action on this Russian blogger's page "Дамба в Санкт-Петербурге". 
The last photo on her page shows a map of the whole system; you can see Kotlin Island and the path of the roadway connecting the north and south parts of the city.
The funny thing about huge cruise ships:
people just can't help but look at them.
I'm sure the folks who run the S-1 gate see large vessels of all types on a regular basis, even so, this guy sat at the window and watched us all the way out. 

The St. Petersburg Dam was a bold idea,
inspired by a need to preserve a city.
More works.

Hopefully the MOSE system in Venice will provide the same kind of protection and "Acqua Alta" will become something from the past that folks talk about now and then.

St. Petersburg is known as "the Venice of the North", and while there are plenty of differences, she does share some similarities as well, including her need to "stem the tide" and keep from getting flooded.


Special thanks to Maria Sigaeva for directing me to the Russian blog "Дamбa B Санкт-Петербурге".

To see St. Petersburg's gondola, check out my post "Гондола!", and "Russian Gondola Under the Flash".


Tamás said...


The same kind of dual swinging arc system is in use in Holland, I think to protect Rotterdam from the sea. There was a Discovery Channel (?) TV special about that.

St. Petersburg was once lying as low as Venezia and got frequently flooded with water much colder than the serene Adriatic. Because of this the canal banks were elevated and the city's lands filled to a higher elevation even back in the tzarist days. The danger of icy acqua alta is less in St. Petersburg, even without the gates.

I heard Venezia's MOSE will be completed in 2014 eventually. That system spans three, wider openings towards the sea, so swing arcs couldn't be made large enough, plus the bora wind would probably break them. The floating flaps should be flexible.

The analogy about Vladimir Putin is quite fitting. The Venice floodgate system and the Sicily straits bridge were the pet projects of Silvio Berlusconi, another authoratic leader. With him out of office, it is difficult to fund MOSE as much as before.

staff said...

The idea ot protect Venice from being flooded by water was born in the seventy's after the flood of 1966. S. Berlusconi has nothing to do with the project called Mo.S.E.
I suggest (especially mr. Feher) to visit the official website that describes (in italian and english) the whole matter.

Tamás said...
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